In the related art, in an audio apparatus such as a sound recording apparatus, a function to cooperate on a plurality of volume controls is known.
Methods of cooperation include a gang function (GANG) in which a level difference between a plurality of volume controls is maintained and an operation is applied, and a link function (LINK) in which a plurality of volume control values are combined and an operation is applied. Among these methods, in the gang function, as a control method when one of the plurality of volume controls reaches a maximum or a minimum, two types are known, one to prohibit a further operation in order to maintain the level difference, and the other to discard the level difference and to allow a continued movement.
JP 3112913 B discloses an apparatus having a sound quality adjustment means for audio outputs of each of front and rear channels, wherein, in a predetermined mode, while a level difference between a front sound quality adjustment setting level and a rear sound quality adjustment setting level is maintained in response to a single operation, the sound quality adjustment setting levels are changed in cooperation with each other. This document further discloses that, when a setting level of one of the channels has reached an upper limit or a lower limit, the level is not changed in a state where the levels are maintained, or the cooperation is cancelled by another key operation to allow change of the level of the other channel.
JP 2002-142286 A discloses that adjacent channels are paired, and, when the mode is set to a gang mode, cooperative control is applied in a state where a relationship of parameter values which are set in the channels is maintained, and, when the mode is set to a link mode, a cooperative control is applied while setting the parameter values of the channels to same values. The document further discloses that, when a parameter value of one of the channels has reached a maximum or a minimum, the relationship between the parameter values is maintained.
In the gang function, in the control method to prohibit further operations in order to maintain the level difference when one of the plurality of volumes has reached the maximum or the minimum, for example, even when the input audio signal level becomes excessive and it is desired to completely reduce the volume as an emergency operation, there is a problem in that not all of the volumes can be completed reduced.